1. Field of the Invention
The present invention relates to a cogeneration system in which waste heat of a drive source such as an engine is used in a heat pump type air conditioner, and, more particularly, to a cogeneration system which includes a heat pump type air conditioner having a simple inner configuration while achieving an enhancement in heating performance.
2. Description of the Related Art
FIG. 1 is a schematic view illustrating a conventional cogeneration system.
As shown in FIG. 1, the conventional cogeneration system includes a generator 2 to generate electricity, a drive source 10, which operates to drive the generator 2, and generates waste heat during the operation thereof, such as an engine (hereinafter, the drive source 10 will be referred to as an “engine”), a waste heat recoverer 20 to recover waste heat generated from the engine 10, and a heat consumer 30 to use the waste heat recovered by the waste heat recoverer 20, such as a thermal storage tank.
The electricity generated from the generator 2 is supplied to various electric home appliances including the heat pump type air conditioner 4 and various home illumination devices.
The generator 2 and engine 10 are disposed in an engine room E defined in a chassis (not shown), which is constructed separately from the heat consumer 30.
The heat pump type air conditioner 4 includes compressors 5, a 4-way valve 6, indoor heat exchangers 7, expansion devices 8, and outdoor heat exchangers 9.
When the heat pump type air conditioner 4 operates in a cooling mode, each compressor 5 compresses a refrigerant introduced thereinto. The compressed refrigerant passes through the 4-way valve 6, outdoor heat exchangers 9, expansion devices 8, indoor heat exchangers 7, and 4-way valve 6, in this order, and returns to the compressors 5. In this case, each outdoor heat exchanger 9 functions as a condenser, and each indoor heat exchanger 7 functions as an evaporator to absorb heat from indoor air.
On the other hand, when the heat pump type air conditioner operates in a heating mode, the refrigerant compressed in each compressor 5 passes through the 4-way valve 6, indoor heat exchangers 7, expansion devices 8, outdoor heat exchangers 9, and 4-way valve 6, in this order, and returns to the compressors 9. In this case, each outdoor heat exchanger 9 functions as an evaporator, and each indoor heat exchanger 7 functions as a condenser to heat indoor air.
The waste heat recoverer 20 includes an exhaust gas heat exchanger 22 to absorb heat from exhaust gas discharged from the engine 10, and a cooling water heat exchanger 24 to absorb heat from cooling water used to cool the engine 10.
The exhaust gas heat exchanger 22 is connected with the heat consumer 30 via a first heat supply line 23. Accordingly, the exhaust gas heat exchanger 22 can transfer the waste heat absorbed from the exhaust gas of the engine 10 to the heat consumer 30 via the first heat supply line 23. As mentioned above, the heat consumer 30 may be a thermal storage tank.
The cooling water heat exchanger 24 is connected with the heat consumer 30 via a second heat supply line 24. Accordingly, the cooling water heat exchanger 24 can transfer the waste heat absorbed from the cooling water of the engine 10 to the heat consumer 30 via the second heat supply line 24.
Meanwhile, where the above-mentioned cogeneration system is configured such that the waste heat of the engine 10 is recovered to be supplied to the heat pump type air conditioner 4 during a heating operation of the heat pump type air conditioner 4, it is possible to achieve an enhancement in the heating efficiency of the heat pump type air conditioner 4.
For example, the cogeneration system may be configured to include an additional outdoor heat exchanger (hereinafter, referred to as a “second outdoor heat exchanger”) disposed in the engine room E to receive waste heat recovered by the exhaust gas heat exchanger 22 and cooling water heat exchanger 24 such that the refrigerant compressed in each compressor 5 is circulated through the indoor heat exchangers 7, expansion devices 8, second outdoor heat exchanger, 4-way valve 6, and compressors 5, in this order, during the heating operation of the heat pump type air conditioner 4, and is circulated through the 4-way valve 6, the outdoor heat exchangers 9, expansion devices 8, indoor heat exchangers 7, 4-way valve 6, and compressors 5, in this order, during the cooling operation of the heat pump type air conditioner 4. In this case, the heat pump type air conditioner 4 can provide a constant heating capacity irrespective of a variation in outdoor temperature when the heat pump type air conditioner 4 operates in the heating mode, and can provide a desired cooling capacity when the heat pump type air conditioner 4 operates in the cooling mode.
In this case, however, the cogeneration system must include at least two bypass conduits and at least two bypass valves, in order to establish a refrigerant bypass path. Although the bypass conduits and bypass valves are typically arranged in the heat pump type air conditioner 4, they cause the heat pump type air conditioner 4 to have a complex inner configuration and an increased size.